Telephone receiver



y 16, 1929. A. P. vows ET AL 1.72l,426 I I TELEPHONE RECEIVER Filed May28, 1926 FLg.2

FL I.

Fig.5.

Inventors. Arthur F. 9mm Joseph: Hutt,

Their Attorney.

Patented July 16, 1929.

UNITED STATES PATENT OFFICE.

*AETHUEP. YOUNG, or KENILWORTH, AND osE H .nurr', E COVENTRY, ENGLAND,-ASSIGNORS ro- GENERAL ELEc'rEro COMPANY, A CORPORATION or N W YORK.

TELEPHONE RECEIVER,

Application filed May 28, 1926, Serial N01 112,362, and in Great BritainJune 10, 1925.

The invention relates to electromagnetic instruments of the kind havinga permanent magnet with pole pieces attached to its ends, andparticularly to telephone 5 receivers or transmitters for use inconnection with wireless or ordinary telephony or telegraphy.

In the patent of Arthur P. Young, No(

1,628,383, granted May 10,1927, and entitled Telephone receivers,thereis described a telephone. receiver, or the like,

having a pole piece of magnetic material which has been shaped to fitclosely around the I end of the permanent mag net on two'opposite sidesthereof, and then pressed so as to make a firm connection therewith. Thepresent invention relates to improvements and modifications of theinvention 'set forth in the. aforesaid co- 20.pending application and isapplicable to loud speakers and apparatus for picking up sounds, as wellas to the ordinary telephone receiver. According to the presentinvention the pole pieces are made of slightly greater width than thepermanent magnet or otherwise arranged so that when they are pressed onto the permanent magnet the metal of the pole pieces flows over theedgesof the permanent magnet, the former beingsofter.

than the latter, with the result that the permanent ma et is to someextentemb'edded in the meta of the pole pieces, and the pole pieces areaccurately positioned with respect to the magnet and are prevented frommoving laterally with respect to the mag net. In instruments of thischaracter, in which the greater part of the magnetic system is embeddedin, composite insulating material, the latter holds the pole pieces intheir correct relative positions. Our present improvement enables thesame magnetic system to be mounted in a casing by meansother'thaii-molding in composite insulating material.

A further feature of our invention consists in providing one or both ofthe pole pieces with lugs. For. instance, each pole piece may have oneor two 'lugs or lateral projections below the fmag'net by means of whichthe magnet assembly is secured-to the casing by rivets, screws, or thelike. Sim; ilarly one or more lugs or lateral -pro1 ecj-' tions may beprovided on one or bothi'pole pieces above the magnet for thepurpose-Ref.

attaching a terminal board in the casing below the coils on whichtheconnections between the coils and telephone leads may be made.

The novel features which webelieve to be characteristic of' ourinvention are set forth with particularity in theappended claims. Ourinvention itself, however,- will best be understood from reference tothe following. specification 'tak en in connection with the accompanvingdrawing in which- Fig. 1 is a top plan view of'a'telephone receiverembodying the features of our invention with the diaphragm and coverremoved; Fig. 2 is a sectional View taken on the line 2-2 of Fig.1; Fig.3 is atransverse sectional view of Fig. 2; Fig. 4 is a' top plan view ofa'telephone' receiver showing a modification of the invention, thediaphragm and cover being removed; and Fig. 5 is a sectional elevationthereof about the line 5 -5. Like reference numerals are used throughoutthe drawings to designate similar parts. 7

With reference to the drawings the magnetic circuit includesquery-shaped pole;

pieces 11 arranged with their curved portions 12 surrounding the ends ofa permanent bar magnet 13 and their straight portions 14 adjacent to oneanother and on the same side of the magnet. The limbs 14 are spacedabove the magnet as at 15 and provided with flat portions 16 which actas seats for the operating coils 17. The width of the pole pieces 11 maybe slightly greater than the width of the-permanent bar magnet 13 sothat when the pole pieces are pressed on to the ends of the barmagnetthe edges of the pole pieces slightly overlie the edges of the magnet,thus forming a pocket and preventing the lateral displacementxof themagnet with respect to the pole pi'c'esr When the pole pieces are madeof metal that is softer than that of the magnets, as is usual, then thewidth of the pole pieces may in the first place'be the same as that ofthe magnet and, if the pressure applied to the pole pieces when they arein position around the magnet ends is suflicient, the metal of the polepieces will .fiow slightly inlateral directions over the edges of themagnet, thus again firmly embedding their bases, by which lugs themagnet assembly 'can be screwed into or riveted to the instrument casing19. Upper'lugs 21 may be formed integrally with the upper portion of thepole pieces, these lugs serving the purpose of carrying a terminal board22 of insulating material upon which the termi- "nals 23 for the cord 24are mounted.

In order to cheapen the constructionstill further we may provide onlytwo lugs for fixing the magnet assembly to the casing, say, one lugformed integrally with each pole piece and extending on opposite sidesof the magnet; and another lug higher upon each pole piece and extendingopposite the other lug thereof, r'or the attachment of the terminalboard. This latter arrangement facilitates the use of rivets forsecuring the magnet assembly-to the casing.

In the arrangement shown 1n Figs. 4 and 5 the magnet assembly is securedby means of a bent "strip 25 passing over the magnet at 26 and rivetedto the casing at 27. end of the strip '25 is brought up at 28430 anchorthe terminalboard 22 and the other end ofthe strip is arrangedto anchorthe two leads of the cord as shown at 29. With this arrangement, it willbe noticed, no lugs .net and to form opposed pole pieces.

3. A telephone receiver or like device comprising a casing and apermanent magnet,

-a pole piece embracing one end of said mag net, said pole piececomprising two parallel portions, each of said parallel portions beingprovided with a projecting lug, one of said lugs being adapted to securesaidinagnet and pole piece in POSltlOIl'lIl the casing and the other ofsaid lugs being adapted to support a terminal board.

In witness whereof, we have hereunto set our hand this 29th day ofApril, 1926.

ARTHUR P. YOUNG JOSEPH HUTT,

